<!DOCTYPE html>
<html>
<head lang="en">
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <link href="dd/common/bootstrap.min.css" rel="stylesheet">
    <style>
        h4 {
            margin-top: 25px;
        }
        .row {
            margin-bottom: 20px;
        }
        .row .row {
            margin-top: 10px;
            margin-bottom: 0;
        }
        [class*="col-"] {
            padding-top: 15px;
            padding-bottom: 15px;
            background-color: #eee;
            background-color: rgba(86,61,124,.15);
            border: 1px solid #ddd;
            border: 1px solid rgba(86,61,124,.2);
        }

        hr {
            margin-top: 40px;
            margin-bottom: 40px;
        }
    </style>
    <title>grid system</title>
</head>
<body>
<body>
<div class="container">

    <div class="page-header">
        <h1>Bootstrap grid examples</h1>
        <p class="lead">Basic grid layouts to get you familiar with building within the Bootstrap grid system.</p>
    </div>

    <h3>Three equal columns</h3>
    <p>Get three equal-width columns <strong>starting at desktops and scaling to large desktops</strong>. On mobile devices, tablets and below, the columns will automatically stack.</p>
    <div class="row">
        <div class="col-md-4">.col-md-4.col-md-4.col-md-4.col-md-4.col-md-4.col-md-4</div>
        <div class="col-md-4">.col-md-4</div>
        <div class="col-md-4">.col-md-4</div>
    </div>

    <h3>Three unequal columns</h3>
    <p>Get three columns <strong>starting at desktops and scaling to large desktops</strong> of various widths. Remember, grid columns should add up to twelve for a single horizontal block. More than that, and columns start stacking no matter the viewport.</p>
    <div class="row">
        <div class="col-md-3">.col-md-3</div>
        <div class="col-md-6">.col-md-6</div>
        <div class="col-md-3">.col-md-3</div>
    </div>

    <h3>Two columns</h3>
    <p>Get two columns <strong>starting at desktops and scaling to large desktops</strong>.</p>
    <div class="row">
        <div class="col-md-8">.col-md-8</div>
        <div class="col-md-4">.col-md-4</div>
    </div>

    <h3>Full width, single column</h3>
    <p class="text-warning">No grid classes are necessary for full-width elements.</p>

    <hr>

    <h3>嵌入式栅格</h3>
    <p>Per the documentation, nesting is easy—just put a row of columns within an existing column. This gives you two columns <strong>starting at desktops and scaling to large desktops</strong>, with another two (equal widths) within the larger column.</p>
    <p>At mobile device sizes, tablets and down, these columns and their nested columns will stack.</p>
    <div class="row">
        <div class="col-md-8">
            .col-md-8
            <div class="row">
                <div class="col-md-1">.col-md-6</div>
                <div class="col-md-6">.col-md-6</div>
            </div>
        </div>
        <div class="col-md-4">.col-md-4</div>
    </div>

    <hr>

    <h3>Mixed: mobile and desktop</h3>
    <p>The Bootstrap 3 grid system has four tiers of classes: xs (phones), sm (tablets), md (desktops), and lg (larger desktops). You can use nearly any combination of these classes to create more dynamic and flexible layouts.</p>
    <p>Each tier of classes scales up, meaning if you plan on setting the same widths for xs and sm, you only need to specify xs.</p>
    <div class="row">
        <div class="col-xs-12 col-md-8">.col-xs-12 .col-md-8</div>
        <div class="col-xs-6 col-md-4">.col-xs-6 .col-md-4</div>
    </div>
    <div class="row">
        <div class="col-xs-6 col-md-4">.col-xs-6 .col-md-4</div>
        <div class="col-xs-6 col-md-4">.col-xs-6 .col-md-4</div>
        <div class="col-xs-6 col-md-4">.col-xs-6 .col-md-4</div>
    </div>
    <div class="row">
        <div class="col-xs-6">.col-xs-6</div>
        <div class="col-xs-6">.col-xs-6</div>
    </div>

    <hr>

    <h3>Mixed: mobile, tablet, and desktop</h3>
    <p></p>
    <div class="row">
        <div class="col-xs-12 col-sm-6 col-lg-8">.col-xs-12 .col-sm-6 .col-lg-8</div>
        <div class="col-xs-6 col-lg-4">.col-xs-6 .col-lg-4</div>
    </div>
    <div class="row">
        <div class="col-xs-6 col-sm-4">.col-xs-6 .col-sm-4</div>
        <div class="col-xs-6 col-sm-4">.col-xs-6 .col-sm-4</div>
        <div class="col-xs-6 col-sm-4">.col-xs-6 .col-sm-4</div>
    </div>

    <hr>

    <h3>Column clearing</h3>
    <p><a href="http://getbootstrap.com/css/#grid-responsive-resets">Clear floats</a> at specific breakpoints to prevent awkward wrapping with uneven content.</p>
    <div class="row">
        <div class="col-xs-6 col-sm-3">
            .col-xs-6 .col-sm-3
            <br>
            Resize your viewport or check it out on your phone for an example.
        </div>
        <div class="col-xs-6 col-sm-3">.col-xs-6 .col-sm-3</div>

        <!-- Add the extra clearfix for only the required viewport -->
        <div class="clearfix visible-xs"></div>

        <div class="col-xs-6 col-sm-3">.col-xs-6 .col-sm-3</div>
        <div class="col-xs-6 col-sm-3">.col-xs-6 .col-sm-3</div>
    </div>

    <hr>

    <h3>Offset, push, and pull resets</h3>
    <p>Reset offsets, pushes, and pulls at specific breakpoints.</p>
    <div class="row">
        <div class="col-sm-5 col-md-6">.col-sm-5 .col-md-6</div>
        <div class="col-sm-5 col-sm-offset-2 col-md-6 col-md-offset-0">.col-sm-5 .col-sm-offset-2 .col-md-6 .col-md-offset-0</div>
    </div>
    <div class="row">
        <div class="col-sm-6 col-md-5 col-lg-6">.col-sm-6 .col-md-5 .col-lg-6</div>
        <div class="col-sm-6 col-md-5 col-md-offset-2 col-lg-6 col-lg-offset-0">.col-sm-6 .col-md-5 .col-md-offset-2 .col-lg-6 .col-lg-offset-0</div>
    </div>
    <h3>Offset</h3>
    <p></p>
</div> <!-- /container -->
</body>
</html>